Machine tool feeding mechanism



July 10, 1962 G. E. LILLIE 3,043,052

MACHINE TooL FEEDING MECHANISM Filed oct. 1, 1959 s sheets-sheet 2 IN VEN TOR. a/z/d/z ZZz' 6.

July 10, 1962 G. E. LILLIE MACHINE TOOL FEEDING MECHANISM 5 Sheets-Sheet 3 Filed Oct. l, 1959 BY m4, 241,59/6@ 3,043,062 MACIME T0011 FEEDING MECHANISlt/I Gordon E. Lillie, Bellows Fails, Vt., assigner to Bryant Chucking Grinder Company, Springfield, Vt., a corpo ration of Vermont Filed (Bet. 1, 1959, Ser. No. 843,710 12 Claims. (Cl. 51-165) This invention relates to grinding machines, land more particularly to means for feeding the grinding wheel toward( and away from the work, the invention being especially adapted for use in internal grinders.

It is an object of the present invention to provide a novel and improved miniature grinder feed mechanism which permits ya highly accurate and closely controlled feed movement of the grinding wheel at variable speeds.

It is another object to provide an improved grinder -feed mechanism of this nature which provides complete indepedence between widely differing high and low speed inputs for the grinding wheel, so that the grinding wheel may approach or clear the work surface at a relatively high speed and be fed into the work yat a relatively low speed.

It is another object to provide completely independent rst and second means to drive a feed unit with the second means driving the unit at a much higher speed than does the first and capable of overriding the rst at any chosen point in the operation cycle.

It is a further object to provide an improved grinder feed mechanism of the above character which may be incorporated in a novel manner with manual adjustment means for the feed position and a compensating arrangement to adjust for wheel wear between operations on successive workpieces.

It is another object to provide a variable speed grinding wheel feed mechanism of this character which is extremely versatile in operation, in which the extreme grinding wheel positions may be varied within Wide limits, and wherein the change from one feed rate to another may occur at any chosen point in the operational cycle.

It is also an object to provide a feed mechanism adaptable to versatile control of the feed rate, feed amount, approach rate, approach amount, and sequence of operation.

Other objects, features, and advantages of the present invention will become apparent from the subsequent descn'ption, taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a schematic view of a grinding wheel spindle supporting means shown in conjunction with the novel feed mechanism.

FIGURE 2is a side elevational view of the feed mechanism showing the relative locations of the feed screw and clutch axes as well as the feed linkage.

FIGURE 3 is a cross-sectional view taken along the line 3 3 of FIGURE 2 and showing the friction clutch construction between the motor drive and the feed operating arm.

FIGURE 4 is a cross-sectional view taken along the line 4 4 of FIGURE 2 and showing the cross-feed connection between the feed arm and the spindle support as well -as the manual adjusting means, and

FIGURE 5 is a partially schematic view showing the relationship between the feed lever and the back-off and terminal stops.

In general terms, the invention includes a feed nut adapted to be connected to a movable part such as a spindle support of an internal grinder -for relatively small parts which must be cross-fed into and out of the workpiece surface for extremely small distances and at -accurately controlled rates.

In the illustrated embodiment,

ice

the feed nut is threaded on a stationary member and hafving an attached end plate engageable with the end of an A adjusting screw, this screw having a threaded portion mounted in the spindle support. screw is rotatable by manual means yfor adjustment purposes and by a compensating arrangement as later de- Iscribed so that the position of the spindle support with respect to the feed nut may be adjusted while the latter is held stationary.

The cross-feed system for rotating the feed nut includes a feed lever secured to the nut and rock-able by a linkage controlled by ya feed operating arm, this arm being rockable on an axis in spaced parallel relation with the cross-feed axis. For rapid cross-feeding, a plurality of reciprocable fluid motors are provided which are engageable with the feed operating arm. A variable speed electric motor is also provided, this motor driving one ele ment of a clutch frictionally connected to the feed operating arm, through reduction gearing. The motor will drive the arm at any desired feed rate, but this rate may be overridden at any time by the uid motors. In this manner, rapid cross-feeding may be achieved during the approach portion of a grinding cycle, as controlled for example by the length of stroke of a uid motor, and the slow speed cross-feed may then take effect, to be followed by a rapid retraction.

Referring more particularly to the drawings, FIGURE 1 illustrates in schematic fashion an application of the novel feed mechanism to a `grinding Wheel spindle support indicated at 11 and supporting a grinding wheel spindle on an axis 12. This support may be carried by a slide 13 movable in la direction parallel to thespindle axis to move the grinding wheel into position for grinding the bore of a part such -as a bearing race. After slide 13 has moved the grinding wheel into position, it is necessary to move support 11 to the left as seen in FIGURE l, thus causing the grinding wheel to approach the work/surface and then continue its movement until the workpiece surface is. reduced the desired amount, after which the wheel is returned to the right as seen in FIGURE 1 and withdrawn from the workpiece.

As seen in FIGURE 4, a stationary housing portion 14 is provided which partially encloses spindle support 11, the latter being urged to the right by a spring 15 shown schematically in FIGURE 1 but not visible in the other figures. Member 11 carries an extension 16 on one side thereof (a similar extension being located at the other side but not shown in the drawings), this extension passing through an anti-friction support 17 in one side of housing 14, so that member 11 is supported for horizontal movement as seen in FIGURE 4. Extension 16 has a central bore and a bushing 18 is mounted therein, the bushing being held in place by a collar 19 and bolts 21. An adjusting screw 22 has a threaded portion 23 threadably mounted within bushing 18, this screw having an Unthreaded portion 24 at its left-hand end supported by bushing 18 and a flange 25 at its midportion. A gear 26 is secured to ange 25, screw 22 having a shaft portion 27 extending to the right of gear 26 as seen in FIGURE 4.

Housing 14 has a portion 2S extending to the right as seen in FIGURE 4, this housing port-ion enclosing gear 26 and supporting a hand adjustment shaft 29 above the gear on an axis parallel to that of screw 22. A pinion 31 is secured to the end of shaft 29 housing portion 28, this pinion meshing with gear 26. A manual crossfeed knob 33 is secured to the other end of shaft 29 for manual adjustment purposes. Housing portion 28 carries a bushing 34 surrounding shaft 29, and one element 35 of a one-way clutch or driving arrangement is rotatably mounted within bushing 34. The other elements 36, 37 and 38 of this one-way drive are so arranged as to achieve The last-mentioned 39. A vertically disposed reciprocable fluid motor 44 is 'carried by housing portion 2S on the left-hand sideY of shaft 29 and is engageable during Vits down-ward stroke with the left-hand end of arm 39 to rotate thearm in a counter-clockwise direction toward the dot-dash line position shown in FIGURE 2. This counter-clockwise movement will not result in any rotation of shaft 29, but as motorY 44 is retracted spring 41 will again be permitted to cause rotation of shaft 29. A locking knob 45 is threadably mounted on the outer end of shaft 29 as seen in FiG- URE 4. When in its loosened position, knob 45 will perrnit rotation of manu-al adjustment knob 33. When knob 45 is tightened however, the compensating arrangement comprising ar-m 39 and spring 41 will be effective to cause pinion 31 to rotate gear 26 for grinding wheel wear com-' pensating purposes as will be later seen.

A bushing 46 is mounted on the outside of housing pontion 28 below bushing 34 and entends outwardly of the housing portion as seen in FIGURE 4. rThe outer end of bushing 46 is threaded, and aV feed nut Y47 is mounted on this threaded portion. An end plate 48 is secured to the outer surface of nut 47 by bolts 49, and the end of shaft 27 is urged against this plate by spring 15, 'an anti-friction support51 being disposed between shaft 27 and bushing 46. A guide bushing 52 is secured to nut 47 by bolt 49 and surrounds bushing 46, anti-friction means 53 being disposed between bushings 52 and 46. A feed lever 54 is likewise secured to nut 47 andY bushing 52, this lever having an irregular shape as seen in FiGURE 2. When lever 54 is rocked from its solid line to its dot-dash line position in FIGURE 2, nut 47 will advance on bushing 46, causing plate 48 to move shaft 27 and thus causing screw 22 and its attached parts, including spindle support "111 to move to the left so as to feed the grinding wheel toward the work. On the other hand, counter-ciockwise rotation of lever 54 in FIGURE 2 will cause retraction of the grinding wheel due to the urging of spring 15. It Vshould be observed that motion of spindle support 1'1 by rotation of shaft 29 Will not be caused by theV advancement of plate 48 to the left in FIGURE 4 (moving both ,screw 22 and bushing 18 to the left in unison) but by the rotation of threaded portion 23 of screw 22 Within bushing 18 (moving bushing 1S to the vleft with respect to screw vBefore considering the novel means for rotating lever 54 at various rates of speed, it would be appropriate to notethe several means for limiting the movement of lever 54 in both directions. A back-off stop in the form o-f a vthreaded member 55 is vertically mounted above the right-hand portion of lever 54 and is engageable thereby as seen in FIGURE 2,y to limit the retracted position of the spindle axis. This stop is'adjustable by a knob 56 in accordance with the internal diameter of the workpiece. A pair of feed stops 57 and 58 are also provided, stop 57 being mounted at the lower portion of lever 54 so as to be engageable by an adjustable abutment 59 carried thereby. Stops 58 and 57 `serve as physical stops and as contacts for controllingelectrical circuitry for the various feed elements, having electrical terminals, 61 and 61' respectively, secured thereto for this punpose. For instance where it is desired that the feed movements stop before member 58 is engaged, an insert stop 62 is provided, this stop being carried by a rockable lever 63 actuatable by a Yiuid motor 64. It will be noted in FIGURE 2 that when leverV 63 is Yrocked from its solid to its dot-dash line posiabutment 69, land will be engaged before engagement of stop S. When lever 63 is withdrawn, stop 53 will be engaged rather than stop 57.

The novel driving means for feed lever `54 is best seen in FIGURES 2 and 3 and comprises a feed operating arm 65 linked to lever 54 by a connecting rod 66, so that clockwise rotation of arm 65 will result inY clockwise rotation of lever 54, and vice versa. Arm 65 is carried by a housing 67 adjacent housing 14. Housing 67 has an antifriction bearing 68 mounted in the` end wall thereof which supports a shaft 69 on which arm 65 is mounted. A worm gear 71 is mounted on shaft 69 inside housing 67, the inner end of shaft 69'being supported by a bearing 72 and supporting plate 73. A worm 74 is rotatably supported at the upper Yportion of' housing 67 and meshes with worm gear 71. An electric motor 75 is mounted on housing 14 and drives wor-rn 74 through an endless belt 76 and sheaves 77 and 7S. Motor 75 is of a variable speed type incorporating reduction gearing and serves as a low speed drive. Arm 65 is connected to shaft 69 by a fr-ictional connection generally indicated at 79. This connection comprises friction clutch members 36 and 81 secured to shaft 69 by a key S2,`and friction members S3 and 84 on arm 65 engageable by members S0 and 81 respectively. A plate 85is carried by the outer end of shaft 69 and carries springs S6 urging member 8i)y against the other members inthe frictional connection 7 9. It will thus be seen that rotation of shaft 69 will result in rotation of arm 65 through frictional connection 79 to drive arm 65 which will, throughy connecting rod 66 rotate lever 54 in the same direction. j. y

The high speed feed input units comprise fluid motors 87, $8 and S9 mounted on the end wall of housing 67 and engageable with arm 65. Motorsr87 and S8 are mounted at the lower end of the housing and are engageable with the lower portion of 65, the latter having contact members 91 and'92 for this purpose. Motor S9 is mounted at the upper end of housing 67 and is engage- 'able with the upper end of arm 65. Fluid motors 87 and 8S, act as quick approach units and may be used alternatively depending on the type of grinding cycle being used. The quick approach amount can be controlled by adjusting the cylinder location or the length of stroke of duid motors 37 and 88. Motor 89 is used as a clearance or back-off unit to cause retraction of the grinding wheel. It will be noted that when any of these motors engages arm 65, it will cause overriding of the normally slow ydrive created by'motorv 75, because of frictional connection '79 between Vthernotor '75 and `arm 65. As soon as any of the -motors 87, SS or 89 ceases its function in driving arm 65, the arm may be driven at the slower rate by motor 75, because slip connection-79 Will maintain the connection between the motor and arm.

It will be seen from' the above description that the cross-feeding operation of the grinding wheel may take various forms depending on requirements. For example, it might be desired to dress the grinding wheel before they nish of each part, that is, as an intermediate step during the grinding of an internal workpiece surface.

and dressedaftereach workpiece is finished, or after several workpieces are iinished, Wear compensating adjustment of the spindle could also be desired after each workpiece orgroupof'workpieces. In any event, appropriate electrical controls couldbe selected to actuate the various motors in their proper sequential `and speed relationship.

For'example, starting with the parts in their solid line position as shown inlFIGURE 2, and assuming that the grinding wheel is inserted within the workpiece bore but is spaced from the bore surface, motor 87 could rst be actuated to rock arm 65Y and therefore lever 54 in a clockwise direction. This would cause 'nut 47 to advance on bushing 46, forcing screw 22 and spindlersupport 11 to the left in FIGURE'4 at a relatively rapid rate. This action could be so controlledv as, to permit the grinding wheel to closely approach the workpiece surface, after which motor 87 would be automatically halted, and shaft 69, driven by motor 75, would drive arm 65 through frictional connection 79 at a slower rate for the grinding portion of the feed stroke. When lever 54 has engaged stop 57 or 58, and after a predetermined time lapse, motor 89 could beractuated to return the parts from their dot-dash line to their solid line position in FIGURE 2. This would permit spring to return spindle support 11 to i-ts retracted position as nut 47 is turned rapidly back on bushing 46, until back-olf stop 55 is engaged. To adjust for wheel wear after a grinding cycle, motor 44 could be retracted to permit compensating rotation of arm 39 by spring 41, this rotation causing rotation of pinion 31, gear 26 and screw 22 through the one-way clutch, screw 22 advancing spindle support 11. Manual adjustment knob 33 could likewise be used when necessary to adjust the spindle support.

If desired, motor 87 could be used for quick approach during a rough grind operation, using spacer 62 to locate the terminal pointV of the quick approach. After rough grinding and dressing of the grinding wheel, motor 88 could be used for quick approach of the finish grind operation, spacer 62 being withdrawn so that stop 58 determines the quick approach terminating point.

While it will be apparent that the preferred embodiment ofthe invention disclosed is well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from ythe proper scope or fair meaning of the subjoined claims.

What is claimed is:

l. In a machine tool feeding mechanism, threadably connected stationary and feed members, means connecting said feed member to a machine tool element, the feed member being adapted to move said machine tool element, first and second drive means independently operable to cause rotation of said feed member, a rockably supported feed operating arm connected to said feed member and movable in unison therewith, a frictional connection between said first drive means and said feed operating arm, and a reciprocable one-way connection between said second drive means and the outer end of said `operating arm.

2. In a machine tool feeding mechanism, threadably connected stationary and feed members, means connecting said feed member to a machine tool element, the feed member being adapted to move said machine tool element, an electric motor for rotating said feed member, a constantly engaged frictional `connection between Asaid motor and feed member, a reciprocable motor adapted to cause high speed rotation of said feed member, and a one-way connection 'between said reciprocable motor and said feed member.

3. In a machine tool feeding mechanism, threadably connected stationary and feed members, means connecting said feed member to a machine tool element, fthe feed member being adapted to move said machine tool element, a lever secured to said feed member, a feed operating arm rockably supported on an axis in spaced parallel relation with the feed member axis, a connection between said arm and lever, constantly rotatable driving means, a frictional connection between said driving means and said feed operating arm, and reciprocable driving means engageable with said arm in one direction, whereby said arm will be caused to override said rotary driving means.

4. In a machine tool feeding mechanism, a stationary member, a feed member threadably mounted on said stationary member, means connecting said feed member to a machine tool element, the feed member being adapted to move said machine tool element, a feed lever secured to said feed member, first and second adjustable stops for limiting the rocking movement of said feed lever in opposite directions, a feed operating arm rotatably mounted on an axis in spaced parallel relation with the feed member axis and connected to said feed lever, rotary .driving means, a frictional connection between said driving means and said arm, a rst reciprocable motor having a one-way connection with one end of said arm, and a second reciprocable motor having a one-way connection with the other end of said arm, whereby said reciprocable motors are adapted to override said rotary driving means.

5. In a machine tool feeding mechanism, a stationary member, a feed member threadably mounted on said stationary member, means connecting said feed member to a machine tool element, the feed member being adapted to movef said machine tool element, a feed lever secured to said feed member, irst and second adjustable stops for limiting the extreme positions of said feed lever, a shaft rotatably supported adjacent with said feed member, an electric motor, reduction gearing between saidV motor and said shaft, a feed operating arm rotatably mounted on said shaft and extending from opposite sides thereof, a frictional connection between said shaft and arm, first and second means for rotation of arm in a given direction, another means yfor rotation in the opposite direction, and means connecting said arm and lever for movement in unison.

6. In Va machine tool feeding mechanism, a movable machine element, a screw threadably connected to and extending from said element, a backing plate, resilient means urging said movable element in -a direction causing said screw to engage said backing plate, means for rotating said screw while held -against said backing plate, whereby feeding movement of said movable element will be caused, a stationary member, means threadably mounting said backing plate on said stationary member for movement toward and away from said screw, first driving means for constantly urging rotation of said mounting means, second driving means for intermittently urging rotation offsaid driving means, and means permitting said second driving means to override said first driving means.

7. The combination according .to claim 6, said rst driving means comprising a rotary drive element,'a frictional driving connection between said element and` said backing plate mounting means, said second driving means comprising a reciprocable drive element, and a positive one-way' driving connection between said reciprocable drive element and said backing plate mounting means.

8. In a machine tool feeding mechanism, threadably connected stationary and feed members, first and second drive means independently operable to cause rotation of said feed member, a frictional connection between said first drive means and said feed member, a one-way connection -between -said second drive means and said feed member, a driven member movable in one direction by rotation of said feed member, and means for moving said driven -mem-ber in said direction independently of said feed member rotation. s

9. In a machine tool feeding mechanism, threadably connected stationary and feed members, first and second drive means independently operable to cause rotation of said feed member, a frictional connection between said first drive means and said feed member, a one-way connection between said second drive means and said feed member, a driven member, an adjusting member threadably mounted in said driven member and engageable by said feed member whereby rotation of said feed member will cause movement of said driven member in one direction, and means for causing rotation of said adjusting member with respect to said driven member independently of movement of said feed member.

l0. In a machine tool feeding mechanism, threadably connected stationary and feed members, first and second drive means independently operable to cause rotation of said feed member, a frictional connection between said first drive means and said feed member, a one-way connection between said second drive means and said feed member, a driven member, an adjusting member threadably mounted in said driven member and engageable by said feed member whereby rotation of said feed member will cause movement of said driven member in one direcf tion, a shaft adjacent said adjusting member and having a geared connection therewith, and means for rocking said shaft* whereby said driven member may be moved independently of said feed member. 11. In :a machine tool feeding mechanism, threadably connected stationary and feed members, rst and second drive means independently operable -to cause rotation of said feed member, a frictional connection between said rst drive'means and said feed member, va one-way connectionbetween said second drive means and said feed member, :a driven member, an adjusting member threadably mounted in said driven member and engageable by said feed member whereby rotation of said feed member will cause movement of saidV driven member in one direction, a shaft adjacent said adjusting member and having a gearedv connection therewith, a rockable member, and a oneway driving connection between said rockable member and said shaft, whereby said driven member may be moved in one direction independently of said feed member. 12. In a machine tool feeding mechanism, threadably connected stationary and -feed members, first and second drive means independently operable to cause rotation of said feed member, a frictional vconnection between said rst drive means and said feed member, a one-way con-v and said shaft, whereby said driven member may be moved in one direction independently of said feed member, and means for manually rotating said shaft independently of said rockable member.

References Cited in the tile of this patent UNITED STATES PATENTS 1,687,398 Silven Oct. 9, 1928 2,334,581 Pyme NOV. 16, 1943 2,571,610 PIiCe Oct. 16, 1951 2,582,610 Swainey Ian. 15, 1952 2,771,715V WOOd NOV. 27, 1956 

